Conventional containers of this character, usually made of plastic material, have a hollow body which is sealed after filling but has a neck with a tab which exposes an outlet for its contents upon being pulled off. If the container is emptied only in part, the neck can be covered with a separately supplied closure cap, preferably after a temporary plugging of the outlet with a wad of cotton; see, in this connection, German printed specification No. 1,965,761. It has also been proposed (see German published application No. 24 46 564) to make the cap integral with the free end of a frangible neck extension which after rupture can thus be inverted to close the outlet.
In all these instances, the container surface surrounding the tab or frangible neck extension is unprotected and therefore subject to contamination by handling and by exposure to the atmosphere; the interior of the closure cap is similarly exposed. Thus, sterility of the product subsequently poured from the outlet cannot be assured unless the container and the cap, after sterilization, are hermetically sealed in an external wrapper which, of course, adds to the cost of the item.
Another problem is that the outlet created by the forcible break-off of a frangible neck extension generally has an irregular and often jagged boundary which is not only unsightly but also potentially dangerous.
A further drawback of conventional disposable containers of flexible plastic material is that the finger pressure required to hold the container body during exposure of the outlet tends to squeeze out some of its contents at the instant of rupture, thus causing spillage of the product on the skin or the garments of the user.